This invention relates to whistles and more particularly, but not exclusively, to a dog whistle of the combination type.
Combination dog whistles have been made for more that 80 years, Nevertheless, it is believed that all operating parameters have not been optimized in a single design and there still tends to be a number of problems associated with such whistles that, as yet, have not been overcome. Combination dog whistles usually have a first mouthpiece at one end with an associated sound chamber having an air vent, and a second mouthpiece at the other end also with an associated sound chamber having an air vent. A pea or cork ball is usually provided in one of the sound chambers.
One problem which arises with conventional combination whistles is that the movement required to change ends to enable the whistle to be blown alternately at both ends is somewhat clumsy and takes a longer time than is desirable when issuing commands to a dog.
Another problem that may occur is the pea (or cork ball) "sticking" in the vent of its sound chamber during blowing. This problem has been around for many years and tends to be a nuisance but has not yet been obviated.
A further problem which is extremely important resides in the fact that when the combination whistle is blown gently it produces a lower frequency than when it is blown very hard; as pressure increases through the blowing range so does the frequency. A large frequency range produced when blowing such whistles gently or hard can cause confusion on the part of the dog trained to respond to the sound of the whistle. Of course, it is of paramount importance that clear command signals can be conveyed to the dog in a reliable manner which can be easily repeated. The conveyance of such reliable signals may make all the difference, for example, between a champion dog winning a trial and the dog simply not hearing and realizing what task he is required to carry out according to the sound of the whistle.
Thus, it is believed to be important that the frequency variation possible when blowing the whistle gently or hard is restricted more than is the case with present whistles of this type which, as previously explained, can cause confusion on the part of the dog.
Equally, it is important that the correct signal can be conveyed to the dog over different working distances and it is believed that parameters have not been optimized in such whistles to convey clear signal information to the dog more particularly over a long distance. Usually one sound chamber of a combination type whistle (not containing a pea) is used to give a quite clear and specific command in a relatively narrow frequency range that will be used for close work (short distances). However, with some dogs (long ear channel dogs) it has been discovered that a wider frequency variation is needed over a longer distance to be more effective. Thus, the features selected to be included in the particular dog whistle combination need to be correlated with the particular type of dog that the whistle is to be used for.